scholarly journals Condensation inside smooth horizontal tubes: Part 1. Survey of the methods of heat-exchange prediction

2015 ◽  
Vol 19 (5) ◽  
pp. 1769-1789 ◽  
Author(s):  
Volodymyr Rifert ◽  
Volodymyr Sereda
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Film Condensation ◽  
Experimental Investigations ◽  
Phase Flow ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Horizontal Tubes

Survey of the works on condensation inside smooth horizontal tubes published from 1955 to 2013 has been performed. Theoretical and experimental investigations, as well as more than 25 methods and correlations for heat transfer prediction are considered. It is shown that accuracy of this prediction depends on the accuracy of volumetric vapor content and pressure drop at the interphase. The necessity of new studies concerning both local heat transfer coefficients and film condensation along tube perimeter and length under annular, stratified and intermediate regimes of phase flow was substantiated. These characteristics being defined will allow determining more precisely the boundaries of the flow regimes and the methods of heat transfer prediction.

The Effect of Regulating Elements on Convective Heat Transfer along Shaped Heat Exchange Surfaces

2013 ◽  
Vol 34 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Jozef Cernecky ◽  
Jan Koniar ◽  
Zuzana Brodnianska
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Cfd Simulation ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Temperature Fields ◽  
Transfer Coefficients ◽  
Heat Transfer Intensification ◽  
Heat Transfer Coefficients ◽  
Forced Air

Abstract The paper deals with a study of the effect of regulating elements on local values of heat transfer coefficients along shaped heat exchange surfaces with forced air convection. The use of combined methods of heat transfer intensification, i.e. a combination of regulating elements with appropriately shaped heat exchange areas seems to be highly effective. The study focused on the analysis of local values of heat transfer coefficients in indicated cuts, in distances expressed as a ratio x/s for 0; 0.33; 0.66 and 1. As can be seen from our findings, in given conditions the regulating elements can increase the values of local heat transfer coefficients along shaped heat exchange surfaces. An optical method of holographic interferometry was used for the experimental research into temperature fields in the vicinity of heat exchange surfaces. The obtained values correspond very well with those of local heat transfer coefficients αx, recorded in a CFD simulation.

Prediction of Horizontal Tubeside Condensation of Pure Components Using Flow Regime Criteria

1980 ◽  
Vol 102 (3) ◽  
pp. 471-476 ◽  
Author(s):  
G. Breber ◽  
J. W. Palen ◽  
J. Taborek
Keyword(s):  
Heat Transfer ◽  
Prediction Method ◽  
Local Heat Transfer ◽  
Flow Regimes ◽  
Local Heat ◽  
Pure Component ◽  
Liquid Volume ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Horizontal Tubes

In order to select the appropriate correlations for prediction of horizontal tubeside condensation heat transfer coefficients, it is necessary to estimate what types of flow patterns exist at various points along the tube. The main criteria required are shown to be the ratio of shear to gravity forces on the condensate film and the ratio of vapor volume to liquid volume. A recently proposed prediction method by Taitel and Dukler is compared with observed flow regimes for condensation in horizontal tubes. The theoretically obtained parameters are shown to characterize the flow regimes well. Based on these parameters, a simplified procedure for prediction of local heat transfer coefficients for pure component condensation in horizontal tubes is proposed.

Local Heat Transfer Coefficients around Horizontal Tubes in Fluidized Beds

1980 ◽  
Vol 102 (1) ◽  
pp. 152-157 ◽  
Author(s):  
R. Chandran ◽  
J. C. Chen ◽  
F. W. Staub
Keyword(s):  
Heat Transfer ◽  
Particle Size ◽  
Fluidized Beds ◽  
Local Heat Transfer ◽  
Local Heat ◽  
General Tendency ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Horizontal Tubes ◽  
System Pressure

The local characteristics of heat transfer from horizontal tubes immersed in fluidized beds were investigated experimentally. Steady-state heat transfer measurements were obtained in air-fluidized beds of glass beads, both for a single tube and a ten-row bare tube bundle. The test results indicated that local heat transfer coefficients are strongly influenced by angular position and gas flow rate, as well as by particle size and system pressure. The heat transfer coefficients, averaged around the circumference of the tube, exhibited a general tendency to increase with decreasing particle size and increasing system pressure. The heat transfer coefficients for a tube in an inner-row position within the bundle were found to be slightly higher than those for a tube in the bottom-row. Comparison of the average heat transfer coefficient data obtained in this study with some of the existing correlations for heat transfer from horizontal tubes showed that the correlations are unsatisfactory.

Measurement of Condensation Heat Transfer Coefficients at Near-Critical Pressures in Refrigerant Blends

2006 ◽  
Vol 129 (8) ◽  
pp. 958-965 ◽  
Author(s):  
Yirong Jiang ◽  
Biswajit Mitra ◽  
Srinivas Garimella ◽  
Ulf C. Andresen
Keyword(s):  
Heat Transfer ◽  
Mass Flux ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Condensation Heat Transfer ◽  
Liquid Region ◽  
Transfer Coefficients ◽  
Reduced Pressure ◽  
Heat Transfer Coefficients ◽  
Horizontal Tubes

This paper presents the results of an experimental study on condensation heat transfer of refrigerant blends R404A and R410A flowing through horizontal tubes of 9.4 and 6.2mm inner diameter at nominal pressures of 80% and 90% of the critical pressure. Local heat transfer coefficients were measured for the mass flux range 200<G<800kg∕m2‐s in small quality increments over the entire vapor-liquid region. Heat transfer coefficients increased with quality and mass flux, while the effect of reduced pressure was not very significant within this range of pressures. The heat transfer coefficients increased with a decrease in diameter.

Local and Average Heat Transfer and Pressure Drop for Refrigerants Evaporating in Horizontal Tubes

1960 ◽  
Vol 82 (3) ◽  
pp. 189-196 ◽  
Author(s):  
M. Altman ◽  
R. H. Norris ◽  
F. W. Staub
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Test Facility ◽  
Transfer Coefficients ◽  
Local Pressure ◽  
Average Heat ◽  
Heat Transfer Coefficients ◽  
Horizontal Tubes

A test facility is described that has been constructed to investigate local heat transfer and pressure drop for evaporating or condensing refrigerants. The empirical method of B. Pierre [1] for correlating the average heat-transfer coefficients of refrigerants evaporating in horizontal tubes is presented in conjunction with the data of several authors [3–6]. Data on local heat-transfer coefficients and pressure drop are presented for Refrigerant-22 evaporating in two 4-ft-long, 0.343-in-ID straight horizontal tubes, and are correlated by a refinement of the curve proposed in [1]. The procedure of Martinelli-Nelson [9] correlated the data for local pressure drop within 15 per cent.

Heat Transfer During Near-Critical-Pressure Condensation of Refrigerant Blends

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Srinivas Garimella ◽  
Ulf C. Andresen ◽  
Biswajit Mitra ◽  
Yirong Jiang ◽  
Brian M. Fronk
Keyword(s):  
Heat Transfer ◽  
Mass Flux ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Liquid Region ◽  
Transfer Coefficients ◽  
Reduced Pressure ◽  
Heat Transfer Coefficients ◽  
Horizontal Tubes ◽  
Wide Range

Heat transfer during condensation of refrigerant blends R404A and R410A flowing through horizontal tubes with 0.76 ≤ D ≤ 9.4 mm at nominal Pr = 0.8–0.9 was investigated. Local heat transfer coefficients were measured for the mass flux range 200 < G < 800 kg m−2 s−1 in small quality increments over the entire vapor–liquid region. Heat transfer coefficients increased with quality and mass flux, while the effect of reduced pressure was not very significant within this range of pressures. The heat transfer coefficients increased with a decrease in diameter. Correlations from the literature were not able to predict the condensation heat transfer coefficient for these fluids at these near-critical pressures over the wide range of tube diameters under consideration. A new flow-regime based model for heat transfer in the wavy, annular, and annular/wavy transition regimes, which predicts 91% of the data within ±25%, is proposed.

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